The present invention relates to an automatic control for an air conditioner and more particularly to a control for reducing the energy consumption of an air conditioner and improving the comfort level within the space being cooled.
In the operation of an air conditioner a compressor is used to compress a refrigerant which then flows through an evaporator whereby heat energy is absorbed from air flowing in close proximity to the evaporator. A fan, driven by an electric motor, is used to provide an air flow over the coils of the evaporator to enhance the transfer of heat energy from the air to the refrigerant in the evaporator. The compressor is also driven by an electric motor and these two motors comprise the bulk of the energy consuming components of the air conditioner, with the compressor motor generally consuming more energy than the fan motor.
In some air conditioner circuits the fan motor is permitted to run continuously while the compressor motor cycles on and off in response to a temperature sensor which provides an indication of room temperature. Control circuits have been provided which permit the fan motor to continue running after the compressor motor has been turned off in order to provide additional air cooling without the expenditure of energy to run the compressor. Such circuits are disclosed in U.S. Pat. Nos. 4,075,864 and 4,094,166.
U.S. Pat. No. 3,635,044 discloses a control circuit which utilizes an automatic timer for periodically energizing the fan of the air conditioner to provide an air flow over the thermostat to detect and sense room air temperature in order to determine whether the compressor needs to be re-energized.